Cap for armor-piercing projectiles.



PATBNTED DBO. 27,' 1904.

C. DAVIS. CAP POR ARMOR PIBRGINGPROJBGTILES.

APPLICATION FILED MAY 9. 1903.

Cleland 17am.

wmwm* l )www UNITED STATES Patented December 27, 1904.

PATENT OFFICE. j

CAP FOR ARMOR-P-IERING PROJECTILES.

SPECIFICATION forming part of Letters Patent No. 778,225, dated December27, 1904.A

Application filed May 9, 1903. Serial No. 156,455.

To @ZZ whom t may concern:

Be it known that I, CLELAND' DAVIS, a lieutenant in the United .StatesNavy,'.stationed lon the United rStates Steamship Oolumbz'cr,

lmeans of which the shock of impact of the projectile is distributedthrough a longer time interval, with consequent 4reduction of maximumstrain, than where ashell alone without a cap is used or than Where theordinary cap is used. 'f Q The theories as to why the soft-metal capinsures better penetration for the shell are' not altogether consistent,nor have they been entirely proven; but that theory most generallyaccepted is as follows: First, when the j hard inextensible face of theplate is struck' by the point of an uncapped projectile the metal in thefaice of the plate does not immediately give way, but there occurs anelastic dishing, in diameter equal to about three times the caliber ofthe projectile. The stress of impact is thus distributed over aconsiderable area, and the concentratedresistance works to suddenly stopthe projectile and causes it to break up through its own inertia. Now inthe case of a capped projectile when the mass consisting of the cap andprojectile strikes the plate there occurs thesalne elastic dishing aspreviously described, but the strain on the projectile is'much reduced,due to the fact that it is not stopped suddenly, as in the previouscase, but continues to. advance through the cap, its passage through thesoft metal of that attachmentbeing comparatively easy, so that when thepoint of the projectile proper reaches the face of the plate theresistance becomes localized and the projectile effects a comparativelyeasy entrance.

It was originally thought that the projectile was smashed von thehard-face, disruption occurring progressively from the point, and

with the idea of protecting the point the socalled fcap was devised. Itwill not be pertinent here to discuss the mechanics of the operation;but I am of the-opinion that the function of the cap is not to protectthe point of the shell, but to smash in the hard face and prepare it forthe entrance of the projectile,

the maximum strain on the shell being at the same time considerablyreduced.

Now there are limitations to the efficiency of the-cap as at presentemployed; It is not eiiicientat oblique impact when the anglefrom thenormal is considerable. Improvement 1n armor gIvIng agreaterdepth ofhard the eiiiciency of the projectile at'oblique angles of impact andalso to lso distribute-the shock of impact as. to reduce themaximumstrain on the projectile, and thus enable it toA get through the platewith its integrity-main- My invention will be understood by reference tothe` accompanying drawings, in

which;

Figure 1 representsa central vertical section through an armor-piercingshellfitted With the impro ved cap. Fig. 2 is-a similar section showinga modified form of the cap,'and Fig. 3 is a similar section showingstill another form of cap constructed according to-my invention.

A represents the main body of the projectile in all the views.

Referring now to Fig. 1, thecap B is at-` vface has so increased themaximum strain on the tached to the projectile A in any convenient way,as by means ofthe screws C. "This cap is provided with a hollowcylindrical shell b and a plate or head L', inclosing the front end ofthe cylinder. This head vmay be made of metal of a dierent degree ofhardness than 'I the cylindrical portion of thc cap, if desired.

In the device shown in Fig. 2 the cap Bl consists of a hol-lowcylinderb2, secured to the IOO ' of metal of adifierent degree of hardness fromthe cylindrical portion of the cap the relative force of the two blows(the. first when the'cyl'-l comprising'a hollow cylinder 'secured overtheent of the United States, is-

shell, as before, :with the head 3 screwed into the forward end of thecylinder.`

In the form of device shown in Fig. 3 an intermediate cap D is provided,-which is rhade of harder metal than the head of the cap B.

The operation of the device is as follows: Referring first to Fig. 1when the lprojectile strikes the armor-plate the cylindrical walls ofthe cap collapse as a result of the blow struck on the face of theplate. Further forward progress of the shell causes-it to strike the`head 'b' of this cylindrical capfand the point' of the projectile boresthrough this head before -it reaches the armor-plate. This produes a'sieconddistinct blow on the face ofthe plate and so weakens thehardface as to effect a comparatively easy entrance for the projectile.

The operation of thedevice shown in Fig. 2 is substantially the same asthat described with reference to Fig. 1. By having the -head b3 inder iscrushed and the second when the head bs is penetrated) may be morereadily adjusted.' Thus for different qualities of armor-plate it may bedesirable to make the head b3 thicker. or thinner or of harder or softermetal, may

:be desired.

f In the form of devicesho'wn in Fig'.- 3 the two actions described aresupplemented by a.. third action, by means of which the cap Disdemolished before the noseof the projectile reaches the armor-plate..`

Having thus described my; invention, what I claim,- and desire to secureby Letters Pat.-

1. A cap -for armor-piercingfprojectiles,

2. A cap for armor-piercing projectiles,`

comprising a h ollow cylinder secured over the 'point of the projectile,'a plate secured to or integral with the forward end of said cylinderand closing the same, and a hoodof harderV metal than saidplatez'nounted over the point of theprojectile inside said hollowcylinder, substantially as and for .the purposesfdescribed.

3. A cap for armor-piercing projectiles;

comprising a massof metal in 'a form of ahollow cylinder mounted overthe point of theV projectile, and a plate ofmetal softer than the metalof the projectile closing the for-wardend of saidcylinder, substantiallyas described-uy l.

4.' A cap for. armorpiercing projectiles,

point.. of .the projectile, aplate of softer metal secured to orintegral with the forward end.

.of said cylinder, and closing the same,'and` a hood ofharder metalthansaid plate mounted poses described.\'..

" In testimony whereof I afhx .my signature inover thepoin't of theprojectile inside said hollow cylinder, substantially'as and forthepur'- ,A

